Indeed. Some of the worst software interfaces I've ever dealt with were fully "dogfooded" and that was the cause; the people writing the software did use it every day but (a) in a very idiosyncratic way and (b) in a specific, very constrained environment.

The devs did use the software, but used it in such a different way from everyone else that when the devs optimized for their own case, it made the software actively worse for everyone else.

Indeed, it's a lesson I learnt the hard way and is much like proofreading something you wrote, you don't see the errors as easily as someone else you asked to proofread it (well until you hit Send then you usually see all of them).